Yes, my male cat has had MANY urinary blockages. We do NOT leave him to go on vacation, unless my sister (very observant) can pet-sit. Either he comes with us or we do not go. It's THAT deadly. He's almost 10, so we are not taking any chances with him.
The special diet was a crock...it did nothing but make him puke. What worked for us was feeding him a natural diet (we use Petguard) and putting vitamin C powder in his food to "acidify" his urine. We are VERY observant of his litterbox habits. If he starts to spend too long in there (first sign that a blockage is coming on), we give him 2 homeopathic treatments called Apis and Arnica. You can buy them at Whole Foods. That generally works pretty quickly. We also give him extra fluids subcutaneously. This "flushes" his bladder. You CANNOT do this if your cat is fully blocked. You can only do it if he is straining and passing urine. Full blockage (passing no urine) is a veternary emergency. Your vet can show you how to do subcutaneous fluids and explain when that is appropriate. We have our own fluid bag, line, and a stash of new, clean needles at home. That kit travels with us wherever we go, since our cat travels with us wherever we go.
We paid a bill of over $1300 the first time that this happened to him. We then switched to a holistic vet, and she taught us how to treat this recurrent issue ourselves. We have only had to have him catherized once over the course of many blockages, and I honestly think that my regular vet would have been able to unblock him w/o the catheter (her partner was working that night). My regular vet also once had to give our cat a dose of Ketamine to relax him, and then she gently squeezed the blockage out and drained his bladder manually. I prefer that to catheterization because there is no risk of bladder puncture or infection, but it takes a VERY experienced vet to do it safely.
Lastly, you can get your cat an operation to have him essentially made into a female down there, which decreases the likelyhood of a blockage. We opted against that because we can manage his condition on our own. The side effect is seriously increased risk of dangerous and symptomless UTI's. As our cat is older, we are too nervous to chance the surgery and the UTI's. Sorry to be so long, but I could write a book on our experiences this topic unfortunately

Feel free to PM me if you want any more info.